This invention relates generally to computer pointing devices, and more particularly to pointing device buttons.
The adoption of the graphical user interface has provided a popular alternative to the command line interface which previously dominated the field of computing. Previously users had to memorize many command names and type in the appropriate command to control the computer. One of the realizations of the graphical user interface has been to make computing easier. To extend computing to a broad population, it is desirable to have an interface which does not require the user to learn and memorize intricate internal operations of the computer. Through the graphical user interface, objects and menus serve as reference choices and enable the design of more intuitive command sequences.
A key tool in working with a graphical user interface is a pointing device. A pointing device is an input device used to control an on-screen cursor for such actions as "pressing" on-screen buttons, choosing among a range of menu items, and selecting objects, cells or groups of words in a document. A pointing device also is used as a stylus in graphical applications for drawing lines and shapes. More recent functions include the "drag and drop" operation in which a displayed item is selected and moved elsewhere on the screen to perform a copy, move or delete operation.
The most common pointing device is referred to as a mouse. The basic features of a mouse are a casing having a generally flat bottom surface, one or more buttons on a top surface, a ball protruding partially from the bottom surface, and a cable for connecting the mouse to the computer. The mouse is designed to be gripped with one hand and held slightly above a reference surface so that the ball remains in contact with the reference surface. As the mouse is moved, the ball rolls along the reference surface generating varying sensing signals at internal contacts adjacent to the ball. Other pointing devices include the graphical tablet, stylus, light pen, joystick, puck, trackball, and more recently, the isometric post (e.g., erasure-head pointing device such as IBM's Trackpoint) and the touchpad, (e.g., Apple Computer's Trackpad). The isometric post resembles a pencil-head eraser and is situated among keys of a keyboard. The isometric post protrudes up above the surrounding keys and is operated by applying directional pressure with a single finger in contact with the post. The touchpad has a generally planar surface and employs field distortion sensing, a form of capacitance sensing technology. The planar surface includes a covered grid of electrical conductors defining an electrical field. When a user touches the surface, the user's fingertip distorts a localized area of the electrical field. The grid is regularly scanned to sense the strength of any distortion at an electrical conductor. The row and column conductors exhibiting distortion indicate the user's finger location. Thus, finger motion, like mouse motion, can be tracked.
With the number of people using computers and the amount of time spent operating a computer increasing, ergonomic considerations for reducing operator fatigue and discomfort are increasingly important. With regard to pointing devices, easy, intuitive operation is desired. A shortcoming of the mouse for example, is the need to repeatedly move one's hand from the keyboard over to a separate mouse device. Improper body position and inconvenient spacing between the keyboard and the mouse can cause fatigue. This invention addresses the ergonomic and ease-of-use concerns associated with pointing devices, and particularly such concerns associated with notebook computer pointing devices.